Worst Babysitter !

So my fiancé’s uncle is dying to babysit our unborn baby of 35 weeks. Btw, he is my fiancé’s aunt’s husband. Not blood related. He doesn’t really have a job, doesn’t have a car, drinks A LOT, smokes cigarettes and is a 50 year old child. He is friendly and nice but I can’t stand his lifestyle choices. His wife works and picks him up from the brewery every night. He doesn’t have a cell phone because he always manages to lose it. My fiancé gives him his old iPhones and he loses them every single time! My fiancé hires him from time to time and he works hard on the job but takes his paycheck right to the brewery where his old car is sitting with flat tires and doesn’t work! When my fiancé was little, he wasn’t allowed to babysit him. I will never know why since the mother passed away a long time ago. He comments on my weight every time I see him since being pregnant. The last time we were eating dinner as a family he had too much to drink and joked how I won’t lose the 35lb baby weight. He then said how he would be the best babysitter ever and really wants to babysit. He yells his name “Uncle Mike” at my belly. He chants my baby’s name and he’s so excited for him to come into this world. But I cannot stand him! He also was molested as a child by one of his family members and I just wouldn’t trust someone like this around my baby. My fiancé said he can’t babysit without supervision like his wife being there but I don’t want him to babysit period! I mean what kind of woman marries or stays married to a man like this...I have to question her too! How do I not let him babysit or go near my child without creating a divide or negativity in the family?